Endoscopic operating techniques have become widely used in a large number of surgical or diagnostic procedures. In these procedures, an endoscopic instrument system, which in particular comprises an endoscope lens system and an endoscopic instrument, is guided through a natural opening of the body, or through an artificial opening created with the aid of an incision, to a target site located inside the body, particularly in a cavity inside the body, where the surgical or diagnostic procedure is to be performed. In many uses, it has proven advantageous to guide a rigid outer shaft through the body opening into the cavity, wherein the interior of the outer shaft receives a rigid endoscope lens system and an endoscopic instrument and also, if appropriate, further channels which can serve, for example, for the introduction of further instruments or as irrigation channels.
An endoscope lens system, often also designated as an “endoscope”, typically has, in the case of a rigid endoscope lens system, a rigid and elongate cylindrical shaft in the distal end area of which, i.e. in the area directed away from the user, an endoscope objective lens is arranged for generating an endoscopic image of the target site. The endoscopic image generated is typically carried through an image carrier, arranged inside the shaft, to the proximal end of the endoscope lens system, i.e. the end near the user. Since there is generally insufficient light in the cavity, a light-guiding system composed of optical fibers is also usually arranged inside the shaft of the endoscope lens system, in order to transport sufficient light to the distal end of the endoscope lens system, where it is used to illuminate the target site.
An endoscopic instrument designed for use in an endoscopic instrument system of said type commonly has an elongate tube which is designed to receive the shaft of the endoscope lens system. A tool for carrying out endoscopic manipulations is arranged at the distal end of the tube, which tool can be controlled, via an elongate transmission element, from the proximal end of the tube, for example by means of a handle arranged at the proximal end. The handle and the proximal end of the endoscope lens system remain outside the body opening during the endoscopic procedure, while the outer shaft, the tube with the tool and the shaft of the endoscope lens system are guided to the target site. The necessary effective length of the outer shaft and of the endoscope lens system and of the tube with the tool is dependent in particular on the nature of the endoscopic procedure and on the access route used.
A cystoscope comprising an outer shaft and an inner element is known from U.S. Pat. Nos. 5,392,765 and 5,549,541, wherein the inner element is positioned in a central cavity of the outer shaft and has an inner channel which comprises a first passage, adapted to receive an endoscope lens system, and a second passage, which is used for guiding a laser fiber. Further areas of the inner channel serve for the conveying of irrigation liquid. The guiding of the laser fiber is not always satisfactory.
An endoscopic instrument for use in an endoscopic instrument system of the type mentioned at the outset is sold by Karl Storz GmbH & Co. KG under the name 10377 HF. The tube for receiving the cylindrical shaft of the endoscope lens system is likewise cylindrical. A tool designed in the form of forceps is arranged at the distal end of the tube, which tool can be actuated by means of a handle, arranged at the proximal end to the tube, via a transmission element designed as a pull rod. The forceps are located in the viewing field of an endoscope lens system guided through the tube, and they thus allow endoscopic manipulations performed with the forceps to be monitored endoscopically; such an instrument is therefore also designated by the expression “optical forceps”. The pull rod is guided in a guide tube extending parallel to the tube, which guide tube extends parallel to the tube and is welded to the outside of the latter. The production of a tube of this type with a welded-on guide tube is relatively complicated and costly.
The endoscope lens system and the tube, the tool and the outer shaft are often provided for repeated use. Therefore, after a surgical intervention, the endoscopic instrument system has to be cleaned and sterilized before being used again. To clean the tube, it is known to flush a cleaning liquid through it. The cleaning of the guide tube is associated with a relatively high cost.